Pendulum CNT-91R User Manual

Measurement Control
Arming can also be used to qualify the stop of
— A selected part of a complex waveform
a measurement. This is called "stop arming" as
opposed to the more common "start arming".
When you use arming, you disable the normal
free-run mode, i.e. individual measurements
must be preceded by a valid start arming signal
transition.
If you use start arming and stop arming to-
g
ether you get an externally controlled me
a-
surement time, a so-called "External Gat
e".
■ Manual Arming
The counters have a manual start arming func-
tion called
HOLD. Here you manually arm the
start of each individual measurement by
pressing the
RESTART key.
Use this manual arming mode to measure sin-
gle-shot phenomena, which are either trig
gered
manually or occur at long intervals. Another
reason for using this manual arming could
simply be to allow sufficient time to write
down individual results.
■ When Do I Use Start Arming?
Fig. 5-1
A synchronization signal starts the
measurement when start arming is
used.
Start arming is useful for measurements of fre-
quency in signals, such as the following:
—
Single-shot events or non-cyclic signals.
—
Pulse signals where pulse width or pulse
positions can vary.
—
Signals with frequency variations versus
signal.
Signal sources that generate complex wave
forms like pulsed RF, pulse bursts, TV line
signals, or sweep signals, usually also produce
a sync signal that coincides with the start of a
sweep, length of an RF burst, or the start of a
TV line. These sync signals can be used to arm
the counter. See Fig. 5-1.
■
When Do I Use Stop Arming?
You normally use stop arming together with
start arming. That means that the external
gating signal controls both the start and the
stop of the measurement. Such a gating signal
can be used to force the counter to measure the
frequency of a pulsed RF signal. Here the
position of the external gate must be inside a
burst. See Fig. 5-2.
Fig. 5-2
Start and stop arming together is
used for burst signal gating.
Note that burst measurements with access to
an external sync signal are performed in the
normal Frequency mode, whereas burst
measurements without an external sync signal
are performed in the self-synchronizing
Frequency Burst mode.
In time interval measurements, you can
use the stop arming signal as a sort of
"external trigger Hold Off signal." Here you
block stop triggering during the external
period. See Fig. 5-3.
time ("profiling").
USER MANUAL ● CNT 9x Series ● Rev.22 February 2020
5-5

Pendulum CNT-91R Specifications

General

Brand	Pendulum
Model	CNT-91R
Category	Measuring Instruments
Language	English